The Best Time to Plant Seedless Concord Grapes in Michigan

Geography and Climate

• The largest danger to grapes in the Southwestern Michigan region is late spring frosts. A sudden frost can reduce grape production by damaging grape vines. Frosts may develop without the presence of freezing temperatures. In southwest Michigan, there is a 90 percent chance of spring frost occurring in late April. This percentage decreases until there is only a 10 percent chance of frost in late May.

Planting Practices

• Concord grapes are a cultivar of the Fox grape, a wild native North American grape variety. This grape variety is bred to be an early-producing grape so that crops may be harvested before fall frost sets in. Grapes require sunlight and warm temperatures to ripen. In many grape-growing operations in Michigan, concord grapes are planted on the south sides of hills to take maximum advantage of sunlight. Where this occurs, plant grapes as soon as the ground can be worked in early spring to give them the maximum amount of time to become established.

Exceptions

• Some growers plant Concord grapes on the north side of hills. These hillsides receive less sun and colder temperatures. Growers plant where there is less sunlight to delay vine growth and grape ripening until after the last frost of spring, to avoid chances of damage. When utilizing this form of growing, the grape vines may also be delayed in planting until this soil warms in late spring.

Dormancy

• Grape vines typically remain dormant until a burst of warm weather awakens them. If you plant your vines during a dormancy period, refrain from training or pruning the vine until after all frost passes. Pruning helps to wake up a vine and stimulate new growth. In the event of frost, this new growth will be damaged. Instead, mulch around grape vines and cover them in the event of sudden frost. Train vines once all danger of frost has passed.